Dear authors,

I have now read the revised manuscript submitted to Solid Earth. Overall the paper is now much more comprehensive and I think it will be a sound contribution to the regional view of the Upper Cambrian to Upper Ordovician magmatism in S-Europe Variscides and its relationships to the major unconformities. However I think some minor issues and doubts need to be corrected before publishing the paper.

A) It is not clear how the authors choose the studied areas in the Iberian Massif. A short description on these criteria could be very useful for the interested reader. Besides, according to up-to-date references (e.g. Martínez Catalán et al 2019; https://doi.org/10.1007/978-3-030-10519-8_4), the Cantabrian, Westasturian-Leonese and Central Iberian zones were part of the Gondwana margin at that time span (broadly autochthon), while in the Galicia -Trás-os-Montes zone (Allochthon), only those units below the Ophiolites are clearly of that affinity (Basal and Parautochthon units). This connects with the non-usual division of the Iberian Massif in the Figure 1 which is not explained in the text. Please better use para-autochthon from the greek Παρά.

Some suggestions about other parts of the Figure 1 (e.g. 82-Saldanha and 90-Urra are not in the map!) are included as comments in the PDF attached to this report.

B). Regarding the geological setting it is important to note that:
B. 1) In the Central Iberian Zone an Upper Ordovician unconformity has been identified in two zones: the Truchas syncline and to the east of the Morais Allochthonous Complex. Data could be raised from Martínez Catalan et al. (1992) and Sarmiento et al. (1999) for the earlier, and from Dias da Silva et al. (2011), Dias da Silva et al. (2014) and Dias da Silva et al. (2016) for the latter. This data may well be included in the paper for their relevance, either for stating the existence of this unconformity, or for refuting it based on later/own data.

B.2) In the oriental areas included in the paper, a short comment is made on the presence of basic volcanic bodies at the considered ages, which are not included in the research. In order to have a more consistent geological setting between the several domains, the Truchas (Truchas syncline) and Santo Adrião (east Morais) basic volcanics (MAGNA map, Dias da Silva et al., 2011; Dias da Silva et al., 2016) could also be included as a minor comment

B.3) As figure 2 is an important asset of the paper, especially for readers with scant knowledge of some areas geology, several improvements would be inserted. In the CIZ the Cambrian sequence reflects only the southern part; lacking the Terreneuvian and Series 2 sequence of the northern part (Díez Balda, 1986). In the Upper Ordovician, the unconformity may well be reflected. A minor mistake exists in La Aquiana limestone’s spelling. In Truchas area, the Upper Ordovician is mainly terrigenous and divided in Casaio, Rozadais and Losadilla formations, being the limestone (La Aquiana) a minor and discontinuous unit; for this reason the now reflected sequence is misleading. In the GTMZ only the Upper Parautochthon must be included, as the Lower Parautochthon is a sequence of Variscan synorogenic origin displaying ages from Uppermost Devonian to Carboniferous (Oliveira et al., 2019). In the UP the sequence does not reflects the proposed for Dias da Silva et al. (2016), as it doesn’t includes the voluminous Middle-Upper Ordovician acid and basic volcanism of the Morais Complex (Peso). The labels and legend must be revised as some mistakes have been found (including lost references which will help to fit data and sketch, especially on the older known ages for the Ollo de Sapo).

I have made some other suggestions along the manuscript in the PDF attached below, please go through them and reply/modify the manuscript accordingly.


References used in this report:

Dias da Silva Í, González Clavijo E, Barba P, Valladares MI, Ugidos JM (2011) Geochemistry of Lower Palaeozoic shales. A case study in a sector of the Iberian Variscides. In: JC Gutiérrez Marco, I Rábano, D García-Bellido (eds) Ordovician of the World - 11th International Symposium on the Ordovician System. Instituto Geológico y Minero de España, Alcalá de Henares, pp 121-125.

Dias da Silva Í (2014) Geología de las Zonas Centro Ibérica y Galicia – Trás-os-Montes en la parte oriental del Complejo de Morais, Portugal/España, vol 45. Serie Nova Terra, vol 45. Instituto Universitario de Geología "Isidro Parga Pondal" - Área de Xeoloxía e Minería do Seminario de Estudos Galegos, Coruña.

Dias da Silva Í, Díez Fernández R, Díez-Montes A, González Clavijo E, Foster DA (2016) Magmatic evolution in the N-Gondwana margin related to the opening of the Rheic Ocean—evidence from the Upper Parautochthon of the Galicia-Trás-os-Montes Zone and from the Central Iberian Zone (NW Iberian Massif). International Journal of Earth Sciences 105 (4):1127-1151.DOI: http://dx.doi.org/10.1007/s00531-015-1232-9

Díez Balda, M.A., 1986. El Complejo Esquisto-Grauváquico, las series paleozoicas, la estructura hercínica al Sur de Salamanca. Act. Salmant. Ciencias, 52, 162 p.

Martínez Catalán, J. R., Hacar Rodríguez, M. P., Villar Alonso, P., Peréz-Estaún, A. & González Lodeiro, F., 1992. Lower Paleozoic extensional tectonics in the limit between the West Asturian-Leonese and Central Iberian Zones of the Variscan Fold-Belt in NW Spain. Geologische Rundschau, 81, (2), 546-560.

J. R. Martínez Catalán, J. Gómez Barreiro, Í. Dias da Silva, M. Chichorro, A. López-Carmona, P. Castiñeiras, J. Abati, P. Andonaegui, J. Fernández-Suárez, P. González Cuadra, and J. M. Benítez-Pérez (2019). Variscan Suture Zone and Suspect Terranes in the NW Iberian Massif: Allochthonous Complexes of the Galicia-Trás os Montes
Zone (NW Iberia).Springer Nature Switzerland AG C. Quesada and J. T. Oliveira (eds.), The Geology of Iberia: A Geodynamic Approach, Regional Geology Reviews, https://doi.org/10.1007/978-3-030-10519-8_4

Oliveira, J.T.; González Clavijo, E.; Alonso, J.L.; Amendáríz, M.; Bahamonde, J.R.; Braid, J.A.; Colmenero, J.R.; Dias Da Silva, Í.; Fernandes, P.; Fernández, L.P.; Gabaldón, V.; Jorge, R.C.G.S.; Machado, G.; Marcos, A.; Merino-Tomé, Ó.; Moreira, N.; Murphy, J.B.; Pinto de Jesus, A.; Quesada, C.; Rodrigues, B.; Rosales, I.; Sanz-López, J.; Súarez, A.; Villa, E.; Piçarra, J.M.; Pereira, Z. (2019). Syn-orogenic Basins. in: C. Quesada and J.T. Oliveira (eds.). The Geology of Iberia: A Geodinamic Approach, Regional Geology Reviews, Springer Nature Switzerland AG 2019, 1-71. https://doi.org/10.1007/978-3-030-10519-8_11
Sarmiento, G.N.; Gutiérrez-Marco, J.C. & Robardet, M. (1999). Conodontos ordovícicos del noroeste de España. Aplicación al modelo de sedimentación de la región limítrofe entre las zonas Asturoccidental-Leeonesa y Centroibérica durante el Ordovícico Superior. Rev. Soc. Geol. España,12 (3-4), 477-500.

Best regards

Juan Gómez Barreiro

Dear authors,

Thanks for reply to my questions. It is rather common to have revisions from editors, to ensure quality and clarity of the submitted work. I see now much more detail and consistency in most of the points I suggested in my previous comments. Reading your replay I suspect that some of my questions were not clearly formulated, I apologize for that. I would like to close this review by clarifying two small but significant issues that need to be resolved before publishing in Solid Earth.

1. CZ, WALZ, CIZ as a par-autochthon
There is no explanation in the text about why in this contribution the CZ, WALZ and CIZ are not considered autochthon, and why they are defined with a new term: (par-)autochthon. It is clear in your comments that you have objections to consider as Variscan autochthon those zones, but the "overthrusting" criterion is not explained anywhere in the text. My concern is not about the idea itself, but the lack of explanation/discussion in the text. If you want to introduce a new classification of the Variscan zones in the Iberian Massif an explanation is required.
Beside, while in the CZ and WALZ there are many and major thrusts, in most of the CIZ, thrusts are very rare. On the other hand, previous works suggest that CZ and WALZ are part of the autochthon because thrusting involves only Gondwanan units (whether belonging to the Gondwana margin or its basement; e.g. Martínez Catalán et al. 2019 and references therein).
The term autochthon in the Iberian Variscan belt describe those zones, which were a part of the supercontinent Gondwana (e.g. its continental margin), while the allochthon refers to the ensemble of exotic units amalgamated to Gondwana during the continental collision in the Variscan orogeny, showing "exotic" features. This apparently simple picture is very complex in detail.
For example, some units below the suture (Middle allochthon or Ophiolitic units) clearly show geological features very similar to the autochthon, (e.g. relatively distal parts of the Gondwana margin) but unique differences, like a high-P Low/Mid-T metamorphism (blueschists/eclogites), reasonably related to a subduction event. The so-called Lower allochthon (or Basal units) and the Parautochthon include those parts of the Gondwana margin that were subducted and relatively far transported (and tectonized) (e.g. Farias et al. 1987; Ribeiro et al. 1990; Gómez Barreiro et al. 2007; Martínez Catalán et al. 2009; Dias da Silva et al. 2014.
In contrast, the area closest to the parautochthon, the CIZ, has practically no thrust faults, and evidence of High-P metamorphism is anecdotic and poorly constrained in tectonic terms (e.g. Barbero and Villaseca, 2000). On the other hand, the WALZ and the CZ show a high level of stacking, but always involving units from Gondwana itself. Therefore WALZ and CZ represent the shortening of the Gondwana margin, but Gondwana. Although at small scale tectonic slices within WALZ and CZ show relative allochthony, nothing suggests that at orogenic scale, the process involves anything other than Gondwana, hence the autochthon.

I agree the classification is imperfect and reveals a debate that is proper to a discipline that is moving forward, (see for example the work of Rubio Pascual and co-workers in this issue). That is why your arguments are important!

In short, I ask you to include your arguments in the text to support the classification of CZ, WALZ and CIZ as a Para-autochthon. I am convinced this will be a sound contribution to the topic. Otherwise, I ask you to correct that classification (e.g. Fig. 1A and related text), including the widely accepted interpretation of CZ, WALZ and CIZ as part of the Variscan autochthon.

2. "Ediacaran-Cambrian lithostratigraphic chart".
I agree a revision of the northern part of the CIZ is needed, however, at least a short sentence is recommended to explain why Díez Balda (1986) and Valladares et al (2000, 2006) are not considered there. That would help and guide the interested reader to understand the state of the art.

I hope now everything is clearer. Please complete those small issues and return the manuscript as soon as possible in order to publish it.

Thanks again for your patience and excellent work

Best regards

Juan Gómez Barreiro

Dear authors,

Thanks for the replay. Please provide a new version with the corrections in Figure 1A including the different zones either in the autochthon or in the allochhon-parautochthon. Besides, a good compromise about Ediacaran-Cambrian lithostratigraphic chart issue is to declare well into the main text or the caption that you are aware of other evidence (e.g. Diaz Balda, Valladares et al...) but you are taken, as a reference for the whole ZCI, the stratigraphic model developed in the southern part of the ZCI, because of its consistency/coherency/ degree of development.

With those modifications the paper will be ready for publishing.

Thanks again for your work

Best regards

Juan Gómez Barreiro

Dear Authors,

After having examined the revised manuscript and your response, I have noticed that some important issues have not been corrected and need further consideration before the acceptance of the manuscript. I will explain below the points:
1. Classification of Variscan Zones into autochthon or parautochthon - allochthon
In your response you said:

"Taking into account that the topic editor proposed us to follow one of two options (either subdividing the “autochthon” or the “allochthon-parautochthon”), we have added a subdivision of the “allochthons” in figure 1A. The topic editor did not indicate which “allochthon-parauthochthon” had to be subdivided from those included in the figure (i.e., the Galicia-Trás-os-Montes Zone, the northern French Massif Central and the northern edges of Sardinia and Corsica) so we have subdivided all of them. The final result is, in our opinion, hardly readable. The reason why we added figures 1B-to-1D was to help any potential reader to find the samples reported in the paper, but the addition of more information in figure A gives rise to an extremely complex figure that is not necessarily useful."


It seems to be a misinterpretation here. In my last and previous comments I clearly explained the need to include the variscan zones (all of them) either in "autochthon" or the "allochthon-parautochthon". In no case has it been requested a subdivision of the "allochthon-parautochthon", but a proper classification of the zones (all of them). In no case was the identification of the complexes, individual units or sub-domains requested, as in a confusing way it appears now it the new version. Considering the scale of the map, this would be a nonsense
Besides, in the last uploaded version, in the Fig. 1A, there are none of the requested changes. The authors maintain their categories: "Variscan autochthons-parautochthons" and "Variscan-allochthons" without any single explanation about the grouping criteria. In the caption it is said this figure is a modification from Pouclet et al. (2017), which indeed is a modification of Ballevre et al. (2009). There are new and updated representations of such a reconstruction (e.g. Ballevre et al. 2014). Some of them come from the authors of this paper, like the Fig 1 of Casas, J.M., Murphy, J.B. 2018. Unfolding the arc: the use of pre-orogenic constraints to assess the evolution of the Variscan belt in Western Europe. Tectonophysics 736, 47–61, where variscan zones' grouping criteria into parautochthon, autochthon and allochthon categories, are clearly defined and show scientific consistency.
I have reviewed again the manuscript text and there are not a single data, at its present form, which support a change in the scheme of variscan zones proposed by Ballevre et al. (2014), Casas and Murphy (2018), Martínez Catalán et al. (2019), Azor et al. (2019)... to name a few ones, so It has to be assumed the authors does not have any scientific evidence to support his new classification. As a consequence please modify the Fig 1A as requested in the previous revision.
Is nevertheless surprising that, instead of making the required changes, the authors have chosen to make a free and imaginative interpretation, adding more errors and confusion to the old figure 1A. I cannot see the purpose of incorporating in the Fig 1A, the name of, for example, the allochthonous complexes of the NW of Iberia, but at the same time leaving as part of the allochthonous, the schistose domain (parautochthon). In parallel, I cannot find any argument in the text supporting the inclusion of e.g. Essarts, Ile-de-Groix or Bois-de-Céné units (Armorican Massif) as part of the autochthon, having been classified as allochthon long time ago (e.g. Ballevre et al. 2014 and references therein). Similar errors are found in the French Central Massif (e.g. Parautochthon Micaschits, etc).
What is the intention of the new addition in the Iberian Allochthon, the Verín-Bragança synform? Should we consider it a new allochthonous complex? Seeing those kind of things, I suspect that not all the co-authors have had access to this version of the article, because it represent a complete nonsense, equivalent to states that the Main Himalayan Thrust is a Neoproterozoic structure.
The authors have to have clear that the problem of the Fig 1A is not, the addition of more information, but the number of errors it has and the absence of arguments supporting their new ideas.

2. Cambro-ordovician Lithostratigraphy

A) "The second question is focused on the (litho-)stratigraphic units previously published exclusively in the Salamanca area of the Central Iberian Zone. As already explained in a former response, we cannot understand why the topic editor requests us to cite some previous works related only to his area of work and ignores other similar reports proposed for other areas included in our work.
It seems obvious that a request has been made to correct what is lacking. What is correct, or what the reviewers have already pointed out, is not included in my report.
What are about other stratigraphic units that, like the Salamanca area, which are not reported in this paper because we selected no samples from there? No interest about them..."

Again the problem here is not a personal interest. The authors are trying to make large-scale correlation based on previous and new datasets. However, the criteria for using some data and not others are not clear. In the answer now it seems that they are only the data of the samples directly obtained for the study. This is not strictly true since they use previous results and data from the literature. In this line, for example, the information published about the Salamanca sector was not selected, but at no point in the text do the authors indicate the criteria they followed in the selection. In the replies the authors give some reasons but never include them in the manuscript.

In connection with this issue, it is surprising what the authors say in their response:
"This paper offers no lithostratigraphic revision of the Central Iberian Zone; this should be obvious for any reader"
And in the caption of the Fig 2 authors said: "Stratigraphic comparison of the Cambro-Ordovician successions from the Central Iberian Zone [...]".

The text and the figure 2 invite the reader to find a correlation of the cambro-ordovician successions across the orogenic zones as a whole (CIZ, GTMZ...). But what he finds is a correlation of certain parts of the zones, taken as a whole. I have no problem with showing a correlation between the specifically sampled zones, but it must be clearly explained in the figure and/or its caption. This can be done by indicating which parts of the existing information in an area have been omitted and why (my proposal), or by indicating that the correlation is made only among the areas sampled in this work, and therefore does not represent a correlation with all the existing data.

Besides, the comment introduced in the Fig 2 caption: "the northern Central Iberian Zone, in the vicinity of Salamanca, is not included here (Díez Balda et al., 1990)" is not correct, because the Diez Balda subdivision applied not only in the Salamanca city, but to the province.
B) "However, we disagree in citing Valladares et al.’s works. Our position is not related to any animosity against the author, Prof. Isabel Valladares, whom we know well. Our refusal is based on a conceptual misleading that was explained in a previous response to the topic editor, but we have no troubles to repeat it.
In her PhD thesis and following papers, Isabel Valladares defined FACIES ASSOCIATIONS (labelled I to XV), not FORMATIONS, and she suggested some broad correlations with previous stratigraphic units. As you know (or you should), a facies association (characterized by an assemblage of facies and useful for environmental interpretations) and a lithostratigraphic unit (characterized by its lithology and useful for mapping) are two completely different things. Therefore, we disagree with your insistence on citing works that describe facies associations as if they were lithostratigraphic formations and thus hampered any stratigraphic correlation. This sounds a serious misconception of geological concepts. "

I sincerely appreciate the explanation about facies and lithostratigraphic units, but again, the problem here is not a "conceptual misleading", but the absence of clear criteria to include some data and refuse others. It seems like the reader has to blindly believe on authors' personal selection. In the response is clear that the authors have a reason for not to use Valladares' works, but refuse to explain them in the main text. Beside, it is important to note that the authors in the Figure 2 caption said:

"Stratigraphic comparison of the Cambro-Ordovician successions [...]"

It might be obvious for the authors that "Stratigraphic... successions" means "only lithostratigraphic units", but, should not be more precise to say "Comparison of the Cambro-Ordovician lithostratigraphy...? It would suddenly clear up the confusion that for an interested reader of a wide-audience journal like Solid Earth could generate.

At this point the affair is still up:
1. - The authors have to complete the required changes in Figure 1A and make sure to include all the variscan zones either in the autochthon or in the allochthon-parautochthon. I suggest following one of the co-authors reconstruction (Fig. 1 Casas & Murphy, 2018) or, e.g. Martínez Catalán et al (2019), see references at the end of this letter.
2. - Please remove the names added in the last version of the Fig. 1A: OC, MC. COC, BZ, Mv, Gu, Br, Ma, Mo, VC, IZ and particularly the "psychedelic" Verín-Bragança syncline (VBS) allochthon.
3. Consider to change in Fig 2 caption "Stratigraphic... successions" by formal stratigraphic definitions like "Cambro-Ordovician lithostratigraphy". In the same caption change " the northern Central Iberian Zone, in the vicinity of Salamanca..." by "the northern Central Iberian Zone, in Salamanca..."
4. Clarify whether in the main text or in the caption of Fig 2 the criteria for data selection. This might be something like "lithostratigraphic data used in the correlation was restricted to the sampled areas".

I am therefore returning the manuscript with a request of minor revision.

Sincerely,

Juan Gómez Barreiro




References:
Ballèvre, M., Martínez Catalán, J.R., López Carmona, A., Abati, J., Díez Fernández, R., Ducassou, C., Pitra, P., Arenas, R., Bosse, V., Castiñeiras, P., Fernández-Suárez, P., Gómez Barreiro, J., Paquette, J.L., Peucat, J.J., Poujol, M., Ruffet, G., Sánchez Martínez, S., 2014. Correlation of the nappe stack in the Ibero-Armorican Arc across the bay of Biscay: a joint French–Spanish Project. In: Schulmann, K., Martínez Catalán, J.R., Lardeaux, J.M., Oggiano, G. (Eds.), The Variscan Orogeny: Extent, Timescale and the Formation of the European Crust. Geological Society, London, Special Publications, vol. 405. pp. 77–113.

Martínez-Catalán, J.R., 2011. Are the oroclines of the Variscan belt related to late Variscan strike-slip tectonics? Terra Nova 23, 241–247. http://dx.doi.org/10.1111/j. 1365-3121.2011.01005.x.

Azor, A., da Silva, Í.D., Barreiro, J.G., González-Clavijo, E., Catalán, J.M., Simancas, J.F., Poyatos, D.M., Pérez-Cáceres, I., Lodeiro, F.G., Expósito, I. and Casas, J.M., 2019. Deformation and Structure. In The geology of Iberia: A geodynamic approach (pp. 307-348). Springer, Cham.

Martínez Catalán, JR., Collett, S., Schulmann, K., Aleksandrowski, P., and Mazur S., 2019 "Correlation of allochthonous terranes and major tectonostratigraphic domains between NW Iberia and the Bohemian Massif, European Variscan belt." International Journal of Earth Sciences: 1-27.

Dear authors

Thanks for your kind reply and effort to improve the quality of your manuscript. Some issues are now clearly solved with the incorporation in the manuscript of precise information. Now every reader can get a clear idea of the meaning and regional scope of your Cambro-Ordovician lithostratigraphic compilation (Figure 2). Well, we have taken a step forward.
However, I still find Figure 1A inaccurate and misleading

I hope that with the attached comments it is clear what remains to be done.

Best regards

Juan Gómez Barreiro

Thank you for your kind and passionate response. I fully agree that the dialectical confrontation of ideas is the basis for science to advance and improve. The process may seem long, as when we learn to read, but the result is certainly worthwhile. Having said this and although the digressions raised by the author are certainly interesting, I think it is important that authors focus their efforts on presenting scientific arguments.
Although reasonable corrections have been made to the text and figures of the article, the answers have never been directed at answering the only question that remained: Why are the Variscan zones classified in the new way in which they appear in Figure 1A? This is a relevant aspect in the context of the special volume that concerns us.
The repeated lack of data in the responses on this point, the surprising use of ad hominem-type argument fallacies in a scientific context, as well as the less elegant resort of threatening the editorial team with withdrawal of the article, clearly indicate that the author's fundamental argument for supporting the model in Figure 1A is "just because".
It is great the author decided to show different reconstructions of the variscan belt in his last letter. This is a good starting point. But please, note that in addition to beautiful figures, there is a clear explanation of the scientific data, and arguments that support those figures, in the text of those articles. This is the only request throughout this editing process that the author seems unwilling to share with everyone. I sincerely hope that the author's recent readings will lead him to explain this in future publications. I have also noticed that some recent references are lacking like this one from 2019: https://doi.org/10.1007/s00531-019-01800-z.

In this line, a published inconsistency is an inconsistency (or error). In Fig1A in Alvaro et al 2020 GSL there are similar inconsistencies in their use of variscan parautochthon, allochthon and autochthon, particularly when they are compared to their main text.
It is much appreciated that the author has specified the extension of the application of his lithostratigraphic data of the Cambrian and Ordovician, initially presented as an over-generalization of the whole of the central Iberian zone, as there were notable absences not initially declared in the manuscript. Similarly, in this last version, he has abandoned the idea of including the Portuguese Southern Zone in the debate, something that was not requested in the revisions, or defining new allochthonous complexes such as that of Verín-Bragança. I am sure that the latter was due to a totally involuntary drawing flaw on the part of the author. As probably is the inclusion of the Schistose Domain among the allochthonous sequences, or perhaps it is simply an incipient color blindness that surreptitiously affects my perception of the chromatic shades of figure 1A.
Fortunately after the last corrections the bulk of the article is not affected by the problem detected in figure 1A and presents excellent data (e.g. geochemistry) that will be very useful to understand the evolution of the Variscan Orogen in a broad sense. I hope that the interested reader will appreciate this balance between what can reasonably be expected from an editing process, and the argumentative licenses that can inevitably lead us all to force arguments and manners because of the passion with which we live this science.
Although it would have been preferable to see the argumentation reflected in the manuscript itself, I refer the reader to the fruitful discussion held throughout the process, to form his/her own idea about the interpretation of the different zones of the Variscan Orogen.

I thank the authors again for their effort and patience.

Cordially yours

Juan Gomez Barreiro